In the present work, aluminum matrix composite (Al-Al2O3) was produced using mechanical alloying in a planetary ball mill. Aluminum granular in size (1-3 mm) with high amount of alumina particles (x(50) = 7.6 lm) were milled up to 500 minutes in a planetary ball mill to indicate the effect of hard particles on the alloying acceleration. The results revealed that high amount of alumina particles promoted the work hardening and decreased the time of mechanical alloying. Further, the particle size analysis indicated that prolonging the milling time caused the particle size to drop from an initial value of 1-3 mm to about 10 lm during the milling. The X-ray diffraction results demonstrated a continuous decrease in crystallite size in Al phase from 350 to 60 nm. Hardness tests illustrated that hardness increased as a function of milling time. The results verified that the produced composites have a homogeneous distribution of alumina particles in the aluminum matrix. The results showed that the aluminum matrix composite can be produced from the granular Al (mm in size) with micron sized Al2O3 by mechanical alloying process. (C) 2014 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.